Virtual Corporate Private Network possibly blocked after upgrade to MacOS 26.1

Idris is right, of course.

Still, you may want to ensure that are not doing anything on your side that could be causing this - any antivirus, cleaners or similar applications? Anything that could be blocking access, like "little snitch"?

Brianb07 wrote:

Because you are all so helpful, here's an update:

So it looks like the problem is with my wifi or router. I am able to get into my corporate network via cellular on my mobile device and my MacBook when using my mobile device as a hotspot.

Or, your company VPN server is configured to allow your old system to connect and is blocking your new connection from your home network.

Most, but not all, corporate VPN provide two modes for connecting:

1. Tunnel All - This mode sends/receives all data between locations.
2. Split Tunnel - This model allows for you to still access local resources at your remote location, in addition, to resources at your company. This mode, may or may not, be allowed by your company's IT Security folks.

If allowed, have you tried switching modes to see if either will work?

Are you using any type of software firewall on your Mac?

This is actually a pretty common scenario.

OS updates often change some of the underlying, low-level stuff that most users won't notice, but that VPNs rely on.

VPN vendors usually have early-access to OS versions so they can test/revise/update their apps, but it takes time to get to the market, for their customers (e.g. your company) to update/validate their servers, and for any application/configuration updates to get pushed out to end users.

It's why many companies have corporate policies that require in-house IT departments to validate and bless OS updates before letting users install. Seems like this one slipped through the net.

How about the macOS networking options to hide your IP address called "Limit IP address tracking" which is enabled by default.

Could the IPv6 play a part as well?

Building on the previous postings

Obviously,  the Companies IT Department knows a lot about Microsoft Windows Environments but has very little actual knowledge / experience when it comes to macOS on Apple Computers 

There are 4 Categories of Third Party Software / Services that are baffling.

In no special order 

1 - Third Party 2 Way Firewalls 

like Lulu and Little Snitch 

2 - Commercial VPNs 

They may not be what one believes they are doing for the computer and what they actually are doing behind the scenes They may also reduce you Internet Speeds by upwards of 30% 

https://gist.github.com/joepie91/5a9909939e6ce7d09e29

VPN: What you need to know - Apple Community

3 - Third Party Security Software 

There are no known Windows-like Viruses in the wild that self replicate and affect macOS, because of the underling UNIX  Foundation and Permission Limitation. 

The Operating System resides in a Sealed and Read Only Volume that cannot be opened by the User nor by Third Party Applications.

The Only thing this Antivirus software is protecting is the Bank Account of the Developers and for zero return to the User aside from the problems this software creates.

Security. Built right in

Mac app security enhancements

The Built in Security  is all that is required to protect the computer.

Protecting against malware in macOS

4 - Third Party Disk Cleaners / Optimizer 

Any Third Party Applications that will interfere with the normal operation of the OS,  is an invitation for disaster. 

Certain Applications maybe available on the Apple Apps Store - this only means the Developer is prepared to pay Apple a percentage on each sale. 

What the Application may do to the computer is up to the User to check this out before purchase

To put the Third Party Disk Cleaner / Optimizer in context and the damages it may have or has already done.

This type of applications can or will Muck Up your User Account ( Home Folder ) of this machine.

It does not touch the Operating System itself unless you consider your User Account ( Home Folder ) as part of the Operating System.

The Operating System is hosed

Even if other people are having similar issues, I don't think that knowledge would do you much good. This is something your corporate IT is going to need to resolve. It's possible that the software they are using needs updating or that the configuration needs adjusting.

You are welcome

Each suggestion, in there own right , is equally valid / good